Stay in awe of your spouse, the love you share and the life you have built together through good times and tough times. Remain thankful for who your spouse is, and remind yourself of the reasons you were drawn to him or her in the first place. Gratitude keeps you focused on what is good in your relationship and helps keep resentment from building up.

It is great to fondly reflect on the good times of your past, but it's not healthy to fixate on some idealized notion that things would be better if you could somehow go back to how it used to be. Instead, choose to believe that the best is always ahead of you. Whether you have been through rough patches or have sailed through blissfully, expect your future to beat anything you have had before.

3) Look at Your Spouse Selflessly

If you have a habit of holding your spouse responsible for your happiness, you definitely need to learn to take that responsibility upon yourself. However, remember that if you view your marriage as being mostly about your rights and what you get out of the bargain, in the long run you are going to end up bitter and disappointed.

4) Look at Your Self Realistically

It pays to have a sober view of your self, being neither overly harsh nor blind to areas you need to work on. Dr. David Schnarch, a clinical psychologist and author of Passionate Marriage, describes marriage as the ultimate people-growing machine. I agree. Every healthy relationship grows and changes over time, and if you want your marriage to stay strong, you have to be willing to grow and change along the way too.

5) Look at Your Relationship Frequently

Watchfulness keeps you from becoming excellent roommates. It requires you to keep your eyes and your heart wide awake to all that is going on in and around you. Consistently ask questions like "how are we doing?" and "is there something more you need from me?"

6) Look Up Continually

This is the last of the six principles, but for my wife and me it is also the most important. We are made up of body, soul and spirit, and we are careful to keep the spiritual component of our marriage front and center, which means we keep the future of our marriage in God's hands.

Whether you know him personally or not, God is for your marriage. He wants you to succeed. It is his desire that your relationship stay strong and endure long, and not just because you both made a lifelong covenant before him, but also because he wants your marriage to be a source of joy and strength, passion and love.

Keep your eyes focused on him, trust in his plans for the future of your marriage, and believe that he has great things in store for you.